While trying to get some rich content sites, we stumbled upon The Molecular Workbench,

Visual, Interactive simulations for Teaching & learning science

“The Molecular Workbench provides visual, interactive computational experiments for teaching and learning science.”

The Molecular Workbench provides a platform for educators to create and publish their own model and simulation-based curriculum materials. MW’s authoring system will help teachers and curriculum developers to create or customize their own online lessons to use models and simulations, which can be run as applets embedded in blogs, wikis, or websites.

We tried download the transistor module and started to play around with it. The tools gave us ability to control the charge on island and see how the electron flow was affected by it.

I am not sure if the pictures above can make justice for the simulation, but will help you to get the concept.

The Molecular Workbench puts a simulation in a learning context. We at Myklassroom.com will try to source the best simulations for our students and will be happy to share them to students around the globe.